The research described in this proposal focuses on the surface membranes and complex carbohydrate constituents of parasitic protozoa of the family Trypanosomatidae including the human pathogen Trypanosoma cruzi and species of the genus Leishmania. The complex carbohydrate components of these protozoa are being studied to determine their chemical composition and their localization within the cell. Specifically, the relationship of these compounds to cell surface and membrane antigens, as well as to antigens circulating in the bloodstream of infected animals to antigens from different sources which cross react in serological tests, are being investigated. The enzymatic composition of the surface membranes of these organisms is being studied. In particular, phosphomonoesterase activities including nucleotidases are being analyzed, as well as ATPase and adenylate cyclase activities. The research plans to focus on the structural aspects of these enzymes including localization, solubilization and isolation in addition to functional characteristics, e.g. their role in nutritional requirements of the protozoa. An additional part of the study will examine the nature of enzymes and antigens shed from the cell surface or secreted through the cell membrane into the culture fluids of these organisms.